Electric motor fuel pumps have been widely used to supply the fuel demand for an operating engine such as in automotive applications. These pumps may be mounted directly within a fuel supply tank with an inlet for drawing liquid fuel from the surrounding tank and an outlet for delivering fuel under pressure to the engine. The electric motor includes a rotor mounted for rotation within a stator in a housing and connected to a source of electrical power for driving the rotor about its axis of rotation. In the pump, an impeller is coupled to the rotor for corotation with the rotor and has a circumferential array of vanes about the periphery of the impeller. One example of a turbine fuel pump of this type is illustrated in U.S. Pat. No. 5,257,916.
Previous fuel pump impellers have vanes which are generally flat, straight and radially outwardly extending. Other impeller vanes have been flat, straight and canted relative to a radius of the impeller. With this general configuration, previous fuel pumps have had an overall efficiency of approximately 20% to 35% and when combined with an electric motor having a 45% to 50% efficiency, the overall efficiency of such electric motor turbine-type fuel pumps is between about 10% to 16%. Thus, there is the continuing need to improve the design and construction of such fuel pumps to increase their efficiency.